CODEWITHSUNDEEP
stringswift
VYT
VYT

Reputation: 1071

How to find index of any first character in a string but not an empty space in swift?

There are strings starting with empty spaces. How can I find index of any first character except of empty space in such strings?

Upvotes: 1

Views: 2147

Answers (2)

Martin R
Martin R

Reputation: 539965

You can use indexOf() with a predicate:

let str = "   Hello world"

// Swift 2:
if let index = str.characters.indexOf({ $0 != " "}) {
    print(index) // 3
}

// Swift 3:
if let index = str.characters.index(where: { $0 != " "}) {
    let pos = str.distance(from: str.startIndex, to: index)
    print(pos) // 3
}

Alternatively, use a regular expression search which can be adapted to more general requests, e.g.

// Swift 2:
if let range = str.rangeOfString("\\S", options: .RegularExpressionSearch) {
    let index = str.startIndex.distanceTo(range.startIndex)
    print(index) // 3
}

// Swift 3:
if let range = str.range(of: "\\S", options: .regularExpression) {
    let pos = str.distance(from: str.startIndex, to: range.lowerBound)
    print(pos) // 3
}

to find the index of the first non-whitespace character in the string.

Upvotes: 5

Caleb
Caleb

Reputation: 5626

You could try an extension like this:

extension String {
    public func indexOfCharacter(char: Character) -> Int? {
        if let index = self.characters.indexOf(char) where String(char) != " "{
            return self.startIndex.distanceTo(index)
        }
        return nil
    }
}

You could also use an extension to find out if the character is a whitespace. Source here.

extension Character {
  func isMemberOfSet(set:NSCharacterSet) -> Bool {
    for char in String( self ).utf16 {
      if set.characterIsMember( char ) {
        return true
      }
    }
    return false
  }
}

Call like this:

let isWhiteSpace = char.isMemberOfSet(NSCharacterSet.whitespaceCharacterSet())

Upvotes: 1

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